SUMMARY (See instructions): Minnesota CCMBM Core B: Muscle Histology and Clinical Repository Core The University of Minnesota Muscular Dystrophy Clinic cares for one of the largest groups of muscular dystrophy patients in the country. Coupled with the comprehensive genetic and histological diagnostic methods developed and maintained by the MDClinic, this population provides a valuable resource for the MDCenter and this NIAMS Core Center for Musculoskeletal Biology and Medicine. As part of its comprehensive clinical diagnostic facility, the MDClinic has established a repository of DNA, fibroblasts, myoblasts, lymphoblastoid cell lines and residual muscle biopsy tissue from subjects with muscle diseases;if specifically supported for research purposes, this Core will provide great value to many currently funded MDCenter research programs, and will be a valuable asset to the greater MD Research Community. Specific Aims of this Core are: 1) Expand the Muscular Dystrophy Database and DNA/Cell Culture/Tissue Repository. Formally establishing this as a research core will facilitate acquisition and distribution of many more samples. 2) To make state-of-the-art histological techniques accessible to fully and complementarity characterize muscle from patients and from animals that model human muscle disease. These methods will allow detailed characterization of diseased muscle as well as comparative studies after treatment in patients and model systems. 3) To provide tissue or cultured cells for detailed analysis of muscle structure and function. MDCenter research on clinically defined specimens will be of value to many basic and translational programs. Specifically, fibroblasts can be studied directly, differentiated into myoblasts for a full range of genetic, biochemical and force generation (Core C) or used to generate IPS cells (Pilot 1) for developmental studies along multiple cell lineages in specified genetic disorders.